Illinois Statutes Chapter 735. Civil Procedure § 5/2-102. Residence of corporations, voluntary unincorporated associations and partnerships defined

(a) Any private corporation or railroad or bridge company, organized under the laws of this State, and any foreign corporation authorized to transact business in this State is a resident of any county in which it has its registered office or other office or is doing business. A foreign corporation not authorized to transact business in this State is a nonresident of this State.

(b) A partnership sued in its firm name is a resident of any county in which any partner resides or in which the partnership has an office or is doing business. A partnership sued in its firm name, of which all partners are nonresidents of this State and which does not have an office or do business in this State, is a nonresident of this State.

(c) A voluntary unincorporated association sued in its own name is a resident of any county in which the association has an office or, if on due inquiry no office can be found, in which any officer of the association resides. A voluntary unincorporated association sued in its own name, of which all its members are nonresidents of this State and which does not have an office or do business in this State, is a nonresident of this State.